Electronic track relay, and railroad signaling system using the same

ABSTRACT

In an electronic track relay, electronic relay circuitry receives an input track signal coded at a pre-determined code rate, and regenerates the input track signal at the pre-determined code rate after a predetermined time delay. A driving circuit is coupled to the electronic relay circuitry for receiving the delayed track signal therefrom and conducting, at the predetermined code rate, at least a power source to at least one of various components in a railroad signaling system. A latching circuit is configured for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system in which the electronic track relay is installed.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 61/306,004, filed on Feb. 19, 2010, the content of which is incorporated by reference herein in its entirety.

This application is also related to U.S. Pat. No. 6,592,081 and U.S. Pat. No. 7,357,359 the contents of which are incorporated by reference herein in their entirety.

BACKGROUND

The disclosure relates to an electronic track relay, and further more particularly, to an electronic track relay that acts as a replacement for electro-magnetic latching, or mag-stick, relays used in railroad signaling systems.

Railroad signaling systems have long incorporated in cab code signaled territories a means to transmit data to trains traveling along the tracks in the form of various AC frequency currents being converted to coded AC current pulses by coupling steady AC currents to the contacts of a relay, whereby, the opening and closure of the contacts found within the electro-magnetic relay, or the turning on and turning off of a plurality of solid-state relays emulating relay contacts found within an electronic type code follower relay at a pre-determined pulse per minute (ppm) code rate to provide for the safe movements of trains as well as providing for a means to protect the trains from broken rail conditions. In non-cab code signaled railroad territories, track conditions are typically conveyed to the trains via a fixed signal located either above or to the right of the track(s) being governed to provide for the aforementioned safe movement of the train(s), in addition to providing for a means to protect the trains from broken rail conditions, as well.

The aforementioned coded, or pulsed, AC currents, typically being, but, not limited to, 40 Hz, 50 Hz, 60 Hz, 91.66 Hz, 100 Hz, and 250 Hz, or, any combination of two of the aforementioned AC current frequencies are transmitted by an electronic code follower relay and coupled to the rail or rails of a railroad track by means of a transformer. The coded AC currents coupled to the rail or rails of a railroad track convey vital safety information to the operator of a train. Additionally, the coded AC currents coupled to a rail or rails of a railroad track are transmitted to adjacent signal locations on the same railroad track for the purpose of conveying track condition information to other adjacent signal locations regulating traffic flow for the same railroad track, thus, further regulating train traffic in a safe manner. Whereas, for example, the coded AC currents convey vital safety data to a train as a means of alerting the operator or driver of the train to the track conditions ahead as well as conveying vital safety data to another train that may be following the first train to ensure a safe distance or spacing is maintained between the two, or more, trains.

Typically, steady AC currents coupled to the contacts of a code follower relay, whereby, the opening and closure of the contacts found within an electro-magnetic or an electronic code follower relay are typically coded, but, not limited to, the following rates of 50, 75, 120, 180, 270, and 420 pulses per minute (ppm) with each code rate providing for a unique signal to be displayed by the train's onboard cab signal, a fixed or wayside signal positioned above or along the governed track(s), for both wayside and cab signal, or singularly, where, some railroads govern the movement of trains by the train's onboard cab signal, whereas, no fixed or wayside signal is provided for the train(s). Therefore, a code follower relay serves as the transmitter for the coded AC currents being coupled to a rail or rails of a railroad track.

FIG. 1 is a schematic diagram of a part of a railroad signaling system 199, which includes an electromagnetic track relay (TR relay) 130, a phase selective unit (PSU) 133, and a code follower relay 137. A code transmitter 138 may also be included. The phase selective unit 133 is coupled to a first section of track rails 197, and the code follower relay 137 is coupled to a second section of track rails 198. The first section of track rails 197 and second section of track rails 198 are separated by insulated rail joints 196.

The phase selective unit 133 receives coded AC currents 195 (i.e., cab code signals traveling along the track rails) from the first section of track rails 197, and then converts the coded AC currents into coded DC currents 194 which are then coupled to a coil in the electromagnetic TR Relay 130. The coded DC currents 194 have a low DC voltage, e.g., a nominal voltage value of 2.3 VDC.

The electromagnetic TR relay 130 receives the coded DC currents 194 (also known as R− voltage or track voltage) from phase selective unit 133. The electromagnetic TR relay 130 then outputs coded DC output currents 193 having a high DC voltage, e.g., a nominal voltage value of 12 VDC, and replicating the code rate that was received from the first section of track rails 197 to drive the code follower relay 137, as well as other signaling components found within the railroad signaling system 199.

The code follower relay 137 outputs coded AC currents 192 replicating the code rate that was received from the first section of track rails 197 onto the second section of track rails 198. A general description of functions and operations of a code follower relay has been given in U.S. Pat. No. 7,357,359 and will not be repeated herein.

The code follower relay 137 may also be controlled by coded DC output pulses 189, e.g., having a nominal voltage of 12 VDC, received from a code transmitter 138, rather than from the electromagnetic TR relay 130. A general description of functions and operations of a code transmitter has been given in U.S. Pat. No. 6,592,081 and will not be repeated herein.

The code transmitter 138, when provided, e.g., at the upstream side of the first section of track rails 197, will drive a code follower relay similar to the code follower relay 137 at a predetermined code rate. The code follower relay's contacts will then switch on and off (i.e., code) 100 Hz AC currents, or, a combination of 100 Hz & 250 Hz AC currents to create the “coded energy” or coded AC currents 195 that is/are coupled to the rails of a railroad track, e.g., the first section of track rails 197.

These coded AC currents 195 then travel along the rails of a railroad track, e.g., first section of track rails 197, to be received at the next signal location, typically one (1) mile away, from the point of origin. The coded 100 Hz AC currents, or, the coded 100 Hz AC currents utilized in the dual frequency AC coded currents, are then coupled to the phase selective unit 133, to then be converted into the low level coded DC currents 194 to drive a coil of the electromagnetic TR relay 130, which in turn drives the code follower relay 137 to output the coded AC currents 192 on the subsequent, second section of track rails 198, as described above.

The electromagnetic TR relay 130 receives yet another input DC currents 191 (also known as R+ voltage or phase voltage) from the phase selective unit 133 that is coupled to a second coil of the electromagnetic TR relay 130. The electromagnetic TR relay 130 also receives power supply from a power source component (not shown) in the railroad signaling system 199.

The electromagnetic TR relay 130 utilizes the phase voltage (R+) or input DC currents 191 to move the armature in the electromagnetic TR relay 130 in order to allow DC current to flow through the Normally Closed (or “Normal”) contacts of the electromagnetic TR relay 130 during the absence of coded DC currents 194 (or the track voltage (R−)) from the phase selective unit 133, or, during the off-time period of the received AC coded rail currents duty cycle. A general description of off-time period, on-time period and duty cycle has been given in U.S. Pat. No. 7,357,359 and will not be repeated herein.

The electromagnetic TR relay 130 is a magnetic stick relay (also referred to as “mag-stick” or “magnetic latching” relay), whereas the armature will remain in its last known position due to magnetic attraction when DC currents are removed from its coil(s). Therefore, an electromagnetic code follower relay is not known to be substitutable for a electromagnetic TR relay.

The wiring of an electromagnetic TR relay also has its specifics. There are basically two types of signaling locations found in a railroad signaling system. One location type is found in the Interlocking (INT) territory where trains can be routed from one track to another. Another location type is found in the Automatic Block Signal (ABS) territory, which is comprised of the main railroad track(s) that run between the Interlocking(s) and/or Controlled Sidings. The internal signal house's wiring for an existing electromagnetic TR relay differs when comparing an INT signal location to an ABS location. Generally, an electromagnetic TR relay's contacts that are designated for DC voltage input currents and DC voltage output currents for an INT location become reverse in function for an ABS location.

The above-described and other operational and functional characteristics of an electromagnetic TR relay are to be taken into consideration when such an electromagnetic TR relay is to be replaced by an electronic TR relay.

BRIEF DESCRIPTION OF DRAWINGS

Several embodiments are illustrated by way of example, and not by limitation, in the figures of the accompanying drawings, wherein elements having the same reference numeral designations represent like elements throughout. Where appropriate, elements having the same reference numeral designations as those in U.S. Pat. No. 7,357,359 represent like elements.

FIG. 1 is a schematic diagram of a part of a railroad signaling system in which electronic track relays in accordance with some embodiments are usable.

FIG. 2 is a functional block diagram of an electronic track relay in accordance with some embodiments.

FIG. 3 is an alternative functional block diagram of an electronic track relay in accordance with some embodiments.

FIG. 4 is a circuit diagram for a phase selective unit in accordance with some embodiments.

FIG. 5 is a functional block diagram for an interlocking type railroad signaling location in accordance with some embodiments.

FIG. 5A is a functional block diagram for a master location type railroad signaling location in accordance with some embodiments.

FIG. 5B is a functional block diagram for a cut section repeater type railroad signaling location in accordance with some embodiments.

FIG. 6 is an alternative circuit diagram of an electronic track relay in accordance with some embodiments that are applicable to the railroad signaling locations of FIGS. 5A and 5B.

FIG. 6A is an alternative circuit diagram of an electronic track relay in accordance with some embodiments that are applicable to the railroad signaling location of FIG. 5.

FIG. 7 is an alternative functional block diagram in accordance with some embodiments of the electronic track relay shown in FIG. 2B.

FIGS. 8 and 8A together show a detailed circuit diagram in accordance with some embodiments realizing the electronic track relay shown in FIG. 7.

FIGS. 9-9J are functional flow charts of a micro-controller's operations of the electronic track relay shown in FIGS. 8 and 8A in accordance with some embodiments.

DETAILED DESCRIPTION

An electronic relay, an electronic track relay, and a railroad signaling system using the electronic track relay in accordance with several embodiments are described. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the specifically disclosed embodiments. It will be apparent, however, that other embodiments may be implemented without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

As noted above, when an electromagnetic TR relay is to be replaced by an electronic TR relay, operational and functional characteristics of such an electromagnetic TR relay are to be taken into consideration, e.g., the ability of a TR relay to maintain its last known position after the coded DC currents are removed, and/or the different wiring requirements at signaling locations of different types.

Some embodiments provide an electronic track relay that acts as a replacement for electromagnetic TR relays. The electronic track relay is based on electronic relay circuitry, for example, as disclosed in U.S. Pat. No. 7,357,359. Any other electronic relay circuitry is also usable as basis for an electronic track relay in accordance with further embodiments. The inclusion of the electronic relay circuitry permits the electronic track relay to accurately replicate an input coded signal to generate an output coded signal at a predetermined code rate.

Besides the electronic relay circuitry, the electronic track relay further includes a latching circuit for ensuring the ability of the electronic track relay to maintain its last known position after the coded DC currents are removed, and/or a self-configuration capability for automatically configuring the electronic track relay in accordance with the type of the signaling location in which the electronic track relay is installed.

FIG. 2_is a functional block diagram of an electronic track relay 210 in accordance with some embodiments. Except for a latching circuit 250, all other elements of electronic track relay 210 are similar to elements having the same reference numeral designations as those in FIG. 2A of U.S. Pat. No. 7,357,359, and define electronic relay circuitry a description of which has been given in U.S. Pat. No. 7,357,359 and will be omitted herein.

FIG. 2_is a functional block diagram of an electronic track relay 230 in accordance with some embodiments. Except for a latching circuit 250, all other elements of electronic track relay 230 are similar to elements having the same reference numeral designations as those in FIG. 2B of U.S. Pat. No. 7,357,359, and define electronic relay circuitry a description of which has been given in U.S. Pat. No. 7,357,359 and will be omitted herein.

The operation of the electronic relay circuitry of an electronic track relay with normally open (Reverse) contacts, in accordance with some embodiments, is similar to that described with respect to FIG. 4 of U.S. Pat. No. 7,357,359. The operation of the electronic relay circuitry of an electronic track relay with normally closed (Normal) contacts, in accordance with some embodiments, is similar to that described with respect to the timing chart shown in FIG. 4A of U.S. Pat. No. 7,357,359.

In the electronic track relay 210 or 230 of FIGS. 2-3, the latching circuit 250 is connected between a micro-processor circuit 26 and one or more SSR driving circuits 260, 270, 280, 290. In one or more embodiments, the electronic track relay 210 or 230 is also coupled to receive a dedicated power supply from a DC-DC converter circuit 22. Other power supply arrangements are implemented in further embodiments.

The latching circuit 250 is configured to perform the latching function of the electronic track relay 210 or 230, as will be detailed herein below with respect to electronic track relay 210.

The microprocessor circuit 26 in electronic track relay 210 is different, in some aspects, from the microprocessor circuit 26 in U.S. Pat. No. 7,357,359 in that the microprocessor circuit 26 in electronic track relay 210, in some embodiments, is programmed or hardwired to determine as to what type of signal location the electronic track relay 210 has been installed within. Based on the determined type of signal location, the micro-processor circuit 26 controls the latching circuit 250 to automatically self-configure the internal DC electrical current path routings in the electronic track relay 210 to ensure that the SSR driving circuits 280, 290, serving as the relay's Normally Open and/or Normally Closed contacts, are properly coupled to a railroad signal system's designated inputs and outputs specific for that type of signal location. In other words, the latching circuit 250 switched the internal current path routings of the electronic track relay 210 between at least two configurations for at least two different types of signal location, e.g., INT and ABS, respectively. Once, the latching circuit 250 has been latched, under control of micro-processor circuit 26, into one of the configurations, the electronic track relay 210 remains in that configuration and replicates coded signals as described in U.S. Pat. No. 7,357,359.

Although FIG. 2 shows a functional block diagram of an electronic track relay 210 in accordance with several embodiments where AC currents are not conducted, this should not be construed in a limiting sense. In further embodiments, solid-state relays featuring AC output currents capabilities are substituted for those solid-state relays having DC output currents capabilities, or, are used in conjunction with the solid-state relays having DC output currents capabilities to provide for both DC and AC output currents capability.

Likewise, FIG. 3 illustrates a functional block diagram of an electronic track relay 230 in accordance with several embodiments where AC currents are not conducted. However, this should not be construed in a limiting sense. In further embodiments, solid-state relays featuring AC output currents capabilities are substituted for those solid-state relays having DC output currents capabilities, or, are used in conjunction with the solid-state relays having DC output currents capabilities to provide for both DC and AC output currents capability.

FIG. 4 depicts a circuit diagram for a phase selective detector unit (or phase selective unit or PSU) 11, for use, e.g., in an AC phase selective type railroad signaling system. PSU 11 functions similar to PSU 133 discussed in FIG. 1, and receives the coded AC currents (e.g., coded AC currents 195) from a rail or rails of a track (e.g., first section of track rails 197), then converts the coded AC currents into coded DC output currents (e.g., coded DC currents 194), also referred to as R− currents. The phase selective detector unit 11 receives another AC currents input from a phase reference voltage transformer (as will be described herein after with respect to FIG.5) and converts the AC currents input into unfiltered DC output currents (e.g., input DC currents 191) also referred to as R+ currents to be coupled to an electronic track relay in accordance with some embodiments.

FIGS. 5, 5A, 5B are functional block diagrams for railroad signaling locations of different types in accordance with some embodiments.

As noted above, the overall railroad track territory can be defined into two basic groups, or, territories. One territory is defined as an Interlocking or Interlocker (INT), where trains may be routed from one track to another. FIG. 5 illustrates the placement of an electronic track relay 520 within a railroad signal system for Interlocking/Interlocker (INT) applications.

For those railroads that maintain an active signal system, where fixed signals (Controlled Sidings) are located above or to the right of the track for governing train movements, this second territory is referred to as Automatic Block Signal (ABS) territory. An ABS territory is comprised of the main line railroad tracks that trains operate over. In a sense, a railroad ABS territory could be described as being a main highway, whereas an INT territory would serve as an interchange.

ABS territories are comprised of two different kinds of signaling locations that occur along the railroad track and at certain intervals in distance. One such signal location is known as being a Master Location (ML), where fixed signals are located above or to the right of the track for governing train movements on the railroad track at, typically, but not restricted to, 2 mile intervals. FIG. 5A illustrates the placement of an electronic track relay 30 within a railroad signal system's Master Location (ML).

A second ABS signal location is known as a Cut Section (CS) typically situated at the midpoint between two Master Locations. The purpose of a Cut Section (CS) is to act as a repeater station to ensure AC and DC current potentials arrive to the next signal location having sufficient amplitude, since AC and/or DC currents traveling long distances via a rail or rails of the track or by other means, such as underground cables, will deplete in amplitude. In some instances, Master Locations having fixed wayside signals governing train movements may be situated at intervals greater than 2 miles, whereby additional Cut Section signal locations may be required to maintain the aforementioned transmitted currents having sufficient operating amplitude(s). FIG. 5B illustrates the placement of an electronic track relay 40 operating within a railroad signal system's Cut Section (CS), where the signal location type serves as a repeater station to regenerate, or refresh, steady and coded currents.

As noted above, magnetic latching or mag-stick relays perform various railroad signaling functions in the aforementioned different types of railroad signaling locations. In some instances, for magnetic latching track relays, the typical designated V+ inputs and V+ outputs in one type of signaling location become reversed in function in a different type signaling location, including, but not limited to, the charging and discharging of electronic component networks comprised of a resistor coupled in series with a capacitor to form what is commonly referred to as being an R/C Network. It is not easy to adapt an electronic TR relay from one type of signaling location to another type.

In contrast, an electronic track relay in accordance with some embodiments is automatically configurable or re-configurable to properly function at more than one types of signaling location, e.g., in all three types of signaling location described above without operator intervention.

It should be noted that the aforementioned different signal location types illustrated in FIGS. 5, 5A, and 5B represent but a few known railroad signaling applications, in which various embodiments are applicable, and should not be construed in a limiting sense to limit the applications of further embodiments only to the aforementioned signal locations.

More specifically, FIG. 5 illustrates a functional block diagram of an INT type railroad signaling location in which an electronic track relay 520 in accordance with some embodiments is provided. Coded AC currents (e.g., 195) received from a rail or rails of a track (e.g., first section of track rails 197) are coupled to a step up transformer 521, where the received coded AC currents 195 are increased to sufficient levels and coupled, as coded AC currents 595, to a phase selective detector unit (PSU) 523, which is similar to PSU 11 described with respect to FIG. 4. At the phase selective detector unit 523, the coded AC currents 595 (received via pins TB1, TB3 in FIG. 4) are converted to coded DC currents (e.g., 194) and coupled (via pin TB5 in FIG. 4) to a control pin (e.g., 75 in FIG. 7) of the electronic track relay 520.

The phase selective decoding unit 523 (or 11 in FIG. 4) receives (via pins TB2, TB7 in FIG. 4) another input source of AC currents 524 coupled from a phase reference transformer 525, also referred to as phase reference voltage in railroad signaling terminology. The phase selective decoding unit 523 compares the phase reference voltage (AC currents 524) to those of the coded AC currents 595 to ensure the AC currents are of correct phase. The phase reference voltage AC currents are then converted by the phase selective decoding unit 523 into unfiltered DC currents (e.g., input DC currents 191), referred to as R+ Voltage in railroad signaling terminology, and is coupled (via pin TB8 in FIG. 4) to a second control pin (e.g., 73 in FIG. 7) of the electronic track relay 520. The electronic track relay 520 then conducts output currents 599 to other components found within a railroad signal system.

Though, FIG. 5 depicts operations for a railroad signal system utilizing an AC currents type signaling system, this should not be construed in a limiting sense. Further embodiments substitute solid-state relays having AC currents output stages with solid-state relays having DC currents output stages or use solid-state relays having DC and AC currents output stages together.

FIG. 5A shows a functional block diagram of an electronic track relay or electro-magnetic-latching relay 30 placed for operations within a Master Location type railroad signaling location utilized within ABS railroad territories, where, typically, a fixed wayside signal is also provided as a means of conveying track conditions to the driver of a train.

In some embodiments, the same or identical electronic track relay that has been used as the electronic track relay 520 for an INT signaling location can be used as the electronic track relay 30 in an ML ABS signaling location. The electronic track relay automatically re-configures itself for functions at the ML ABS signaling location upon initialization as will be described herein below.

Likewise, in some embodiments, the same or identical electronic track relay that has been used as the electronic track relay 30 for an ML ABS signaling location can be used as the electronic track relay 520 in an INT signaling location. The electronic track relay automatically re-configures itself for functions at the INT signaling location upon initialization as will be described herein below.

Elements 31, 33, 35 in FIG. 5A are similar to elements 521, 523, 525 in FIG.5, respectively. Therefore, the aforementioned operations described with respect to FIG. 5 are also applicable to the relevant elements of FIG. 5A, and will not be repeated herein.

As depicted in FIG. 5A, DC output currents 593 from the electronic track relay 30 are coupled to the coil of an electro-magnetic code follower relay or to a control pin for an electronic code follower relay 37 such as that disclosed in U.S. Pat. No. 7,357,359. The code follower relay 37 will conduct coded output currents 592 to a step down transformer 39, in addition to conducting output currents 599 to other components found with a railroad signaling system. The transformer 39 will then couple AC coded currents 192 to a rail or rails of track (e.g., second section of track rails 198) to convey track conditions to the driver of a train. Thus, the coded AC currents 192 are also transmitted to the next railroad signal location to further govern train traffic.

FIG. 5B shows a functional block diagram of an electronic track relay or electro-magnetic-latching relay 40 placed for operations within a Cut Section or Repeater type railroad signaling location utilized within ABS railroad territories, where, received AC and DC currents conducted from a previous railroad signaling location are received by the Cut Section are then repeated or re-transmitted in exact form having refreshed currents to ensure the repeated currents are received by the next signaling location being of sufficient amplitude.

In some embodiments, the electronic track relay 40 is configured identically to the electronic track relay 30 of FIG. 5A.

Elements 41, 43, 45, 47, 49 in FIG. 5B are similar to elements 31, 33, 35, 37, 39 in FIG. 5A, respectively. Therefore, the aforementioned operations described with respect to FIG. 5A are also applicable to the relevant elements of FIG. 5B, and will not be repeated herein. The primary difference between the signaling locations in FIGS. 5A and 5B is the absence of additional output currents 599 in the Cut Section signaling location of FIG. 5B.

As noted above, for some railroad signaling applications, the DC currents coupled to a relay can become reversed in functions, whereas, relay contacts that serve as V+ input currents and those serving as V+ output currents in ABS type railroad signaling locations can become reversed in function when the same relay is utilized for an INT type signaling locations. An electronic track relay in accordance with some embodiments advantageously re-configure itself to operate in various types of signaling applications without modifications being made to the hardware of the electronic track relay nor signal location wiring changes be made.

FIGS. 6 and 6A are alternative circuit diagrams 60, 62 of the same electronic track relay in accordance with some embodiments for use in an ABS railroad signaling locations of FIGS. 5A and 5B, and in an INT railroad signaling location of FIG.5, respectively. The description of FIGS. 6 and 6A will be best given below in conjunction with FIGS. 8 and 8A.

FIG. 7 shows a functional block diagram of an electronic track relay 701 in accordance with several embodiments which are based on the electronic track relay shown in FIG. 2B. In FIG. 7, elements 71, 711, 74, 78, 713, 715, 717, and 719 are similar to elements 20, 22, 26, 28, 260, 270, 280, and 290 of FIG. 2B, respectively, which are, as discussed above are similar to elements having the same reference numeral designations as those in FIG. 2B of U.S. Pat. No. 7,357,359.

In some embodiments, the use of a trigger relay 70 is a unique aspect. As can be seen in FIG. 7, trigger relay 70 is coupled to the R+ output 73 of a phase selective detector unit (e.g., 11, 523, 33, 43) of a railroad signaling system for receiving therefrom input DC signals 191, steady signals, or no signals. An input voltage from dedicated power source 711 is coupled to trigger relay 70 which then outputs an isolated DC power source from dedicated power source 711 for the triggering of micro-controller circuit 74. In essence, trigger relay 70 replicates the received input DC signals 191, steady signals, or no signals from the R+ output 73 of a phase selective detector unit of a railroad signaling system, but, outputs these received signals as an isolated and dedicated coded signals, steady signals, or no signals to be coupled to micro-controller circuit 74. Therefore, not only does dedicated power source 711 act as a source of power for micro-controller circuit 74, dedicated power source 711 is also coded into square wave signals (or presented as a steady signal or as no signals) by trigger relay 70 whose output is then coupled to control micro-controller circuit 74, as depicted in FIG. 7. The R+ DC output currents (e.g., 191) received from the phase selective detector unit via the R+ output 73 coupled to trigger relay 70 represent the AC currents received from a phase reference transformer (e.g., 525) by the phase selective detector unit which converts the received phase reference transformer AC currents into DC currents 191.

In some embodiments, the use of a trigger relay 72 is a unique aspect. As can be seen in FIG. 7, trigger relay 72 is coupled to the R− output 75 of a phase selective detector unit (e.g., 11, 523, 33, 43) of a railroad signaling system for receiving therefrom DC coded signals (e.g., 194) or no signals. An input voltage from dedicated power source 711 is coupled to trigger relay 72 which then outputs an isolated DC power source from dedicated power source 711 for the triggering of micro-controller circuit 74. In essence, trigger relay 72 replicates the received coded signals (e.g., 194) or no signals from the R− output 75 of the phase selective detector unit of a railroad signaling system, but, outputs these received signals as an isolated and dedicated coded signals (or no signals) to be coupled to micro-controller circuit 74. Therefore, not only does dedicated power source 711 act as a source of power for micro-controller circuit 74, dedicated power source 711 is also coded into square wave signals (or presented as no signals) by trigger relay 72 whose output is then coupled to control micro-controller circuit 74, as depicted in FIG. 7. The R− DC output currents (e.g., 194) received from the phase selective detector unit via a R− output 75 coupled to trigger relay 72 represent the coded AC track currents (e.g., 195, 595) received from a rail or rails of a track (e.g., first section of track rails 197) by the phase selective detector unit which then converts the received coded AC track currents (e.g., 595) into DC coded currents (e.g., 194).

In some embodiments, a unique aspect is the use of opto-coupler circuit 76 for receiving DC V+ currents (via V+ Inputs pins) from a railroad signal system, thereby, ascertaining the type of signal system location, i.e., an INT or ABS type railroad signaling location, the electronic track relay 701 has been installed within. An input voltage from dedicated power source 711 is coupled to opto-coupler circuit 76 which then outputs an isolated DC power source from dedicated power source 711 for the triggering of micro-controller circuit 74.

In some embodiments, a unique aspect is the use of dual output solid-state relay 700 for providing drive currents to the appropriate coils of magnetic latching relays 702 and 704 (also referred to herein as K7 and K8, respectively). Once micro-controller circuit 74 has ascertained the type of signal system location, i.e., an INT or ABS type railroad signaling location, the electronic track relay 701 has been installed within from the received input currents coupled from opto-coupler circuit 76, micro-controller circuit 74 initiates drive currents coupled to an appropriate control pin of solid-state relay 700.

In some embodiments, a unique aspect is the use of dual coil magnetic latching relays 702 and 704 for coupling the received V+ DC input currents from a railroad signal system to input pin 1 of one or more of the appropriate solid-state relay(s) 713, 715, 717, and 719 (also referred to herein as K6, K5, K4 and K3, respectively) and for coupling V+ DC output currents from one or more of the aforementioned solid-state relay(s)' output pin 2 to various railroad signal system components. The one or more of the aforementioned solid-state relays K3-K6 emulate normally closed and normally open relay contacts for the electronic track relay 701. Specifically, magnetic latching relays 702 and 704 each feature two internal coils, designated as being SET and RESET. The SET coil for magnetic latching relay 702 is serially coupled to the SET coil for magnetic latching relay 704 for configuring the electronic relay 701 for INT signal location use. The RESET coil for magnetic latching relay 702 is serially coupled to the RESET coil for magnetic latching relay 704 for configuring the electronic relay 701 for ABS location use.

In embodiments where magnetic latching relays are used to implement the latching circuit (e.g., 250 in FIGS. 2-3), the electronic track relay is also referred to as electronic magnetic latching relay.

Other arrangements with other types of latching relays, or other latching circuits, or other connections between the latching relays, or other numbers of latching relays or circuits etc., are not excluded. It should be noted, however, that pure electronic latching circuits, such as those based on diode bridge rectifiers, might incur additive voltage drops and/or cause an undesirable decrease, or losses, in the charging DC currents.

In some embodiments, a unique aspect is the electronic track relay 701's periodic self check feature to ensure the electronic track relay 701 maintains its pre-determined configuration for either ABS location use or INT location use. The serial coupling of an output current from a pin of micro-controller circuit 74 to a contact in magnetic latching relay 702 which is then serially coupled to a contact in magnetic latching relay 704, which is then coupled to another pin of micro-controller circuit 74 to receive the originally transmitted check currents from a pin of micro-controller circuit 74 ensuring the magnetic latching relays 702, 704 remain in correspondence, i.e., ensuring that the electronic track relay 701 maintains its desired configuration for either ABS location use or INT location use. If magnetic latching relay 702 and magnetic latching relay 704 are found to be out of correspondence, drive currents are then transmitted by micro-controller circuit 74 to the appropriate control pin of dual output solid-state relay 700, thereby, coupling drive currents to the appropriate coils in magnetic latching relays 702 and 704 to return the magnetic latching relays into proper correspondence for ABS location or INT location mode, as had been determined by the electronic track relay 701 when the electronic relay 701 had initially been installed into one of the aforementioned railroad signal location types.

The electronic track relay 701 shown in FIG. 7 is implemented in accordance with some embodiments by a micro-controller IC based circuit 80, which is illustrated in FIGS. 8 and 8A. The micro-controller IC based circuit 80 includes several elements which are similar to those described with respect to electronic code follower relay 51 in FIG. 5A of U.S. Pat. No. 7,357,359, and will not be described in detail herein.

The electronic track relay 80 shown in FIG. 8 includes a visual indicator circuitry 81 including LED D9 for Track (TK) contact output currents and LED D8 for Phase (PH) contact output currents. The LED D9 and LED D8 are similar in function to visual indicators LED D5 for fronts contact output currents and LED D4 for backs contact output currents, respectively, described with respect to FIG. 5A in U.S. Pat. No. 7,357,359.

The electronic track relay 80 shown in FIG. 8 includes an opto-coupler circuit 83 comprising a 4-channel opto-coupler integrated circuit U3 which is similar to integrated circuit U3 described with respect to FIG. 5A in U.S. Pat. No. 7,357,359. The 4-channel opto-coupler integrated circuit U3 of electronic track relay 80 is coupled to a bussed resistors network RN3 which provides drive currents to a plurality of solid-state relays K3-K6 emulating the normally closed and normally open relay contact sets. The opto-coupler circuit 83 of FIGS. 8-8A corresponds to opto-coupler 78 of FIG. 7.

The electronic track relay 80 shown in FIG. 8 includes a plurality of solid-state relays 85 emulating normally closed and normally open relay contact sets for conducting DC currents having time delayed operational features from drive currents commanded from micro-controller integrated circuit U2 for operating solid-state relays K3, K4, K5, and K6 emulating Form C break before make relay contact operations. The solid-state relays K3, K4, K5, and K6 of the electronic track relay 80 are similar in operation to solid-state relays K2, K3, K6, and K7, respectively, described with respect to FIG. 5A in U.S. Pat. No. 7,357,359.

The electronic track relay 80 shown in FIG. 8 includes a micro-controller circuit 87 comprising a micro-controller integrated circuit U2 coupled to bussed resistor networks RN1 and RN2. In certain aspects, micro-controller integrated circuit U2 of electronic track relay 80 is similar to integrated circuit U2 described with respect to FIG. 5A in U.S. Pat. No. 7,357,359. For example, the micro-controller integrated circuit U2 of the electronic track relay 80 commands output drive currents for operating a plurality of solid-state relays K3-K6 emulating the normally closed and normally open contacts typically found with an electro-magnetic relays operating within a railroad signal system, as described with respect to integrated circuit U2 in FIG. 5A in U.S. Pat. No. 7,357,359. The micro-controller integrated circuit U2 of the electronic track relay 80 also provides for time delayed output drive currents ensuring the aforementioned solid-state relays operate as Form C type break before make relay contact operations, similarly to integrated circuit U2 in FIG. 5A in U.S. Pat. No. 7,357,359.

In other aspects as will be described herein below, the micro-controller integrated circuit U2 of the electronic track relay 80 is different from integrated circuit U2 in FIG. 5A in U.S. Pat. No. 7,357,359. The micro-controller circuit 87 of FIGS. 8-8A corresponds to micro-controller IC 74 of FIG. 7.

The electronic track relay 80 shown in FIG. 8 includes a dedicated DC power supply circuit 89 which is similar to the power supply circuit associated with the integrated circuit U1 described with respect to FIG. 5A in U.S. Pat. No. 7,357,359. Specifically, dedicated DC power supply circuit 89 includes DC-DC converter U1, capacitors C1 and C2, and resistor R2 receiving input DC currents from a railroad signal system and converting the received DC currents into an isolated form of DC currents being free of transients and electrical noise for powering electronic track relay 80. The dedicated DC power supply circuit 89 of FIGS. 8-8A corresponds to dedicated power source 711 of FIG. 7.

In the embodiment specifically illustrated FIGS. 8 and 8A, the connection points to a GRS/Alstom AC Phase Selective Can Code Signal System are represented by numbered circles indicating the serial connections made to the track relay 80. Such connections should not be construed in a limiting sense as one with ordinary skill in the art can readily contemplate other circuit arrangements.

In the subsequent description, a phase selective detector unit is understood as any of PSUs 11, 523, 33, 43 or any other type of phase selective detector unit provided in a railroad signaling system.

In an aspect, solid-state relay K1 in FIGS. 8-8A corresponds to the phase trigger relay 70 of FIG. 7. As depicted in FIG. 8, solid-state relay K1 is a phase voltage trigger relay. Pin 1 of relay K1 is a positive DC currents input, and pin 2 of K1 is a positive DC currents output. Pin 1 of relay K1 is coupled to positive output pin 6 of DC-DC converter U1 to receive dedicated positive DC currents. Pin 3 of the relay K1 is a positive control. Pin 4 is a negative control and is coupled to pin 7 of DC-DC converter U1 to receive dedicated negative currents. Pin 7 of DC-DC converter U1 serves as the electronic track relay circuitry's ground reference. When control currents are coupled to pin 3 and pin 4 of relay K1, pin 2 of the relay K1 will conduct positive output DC currents to a load.

Control pin 3 for phase voltage trigger relay K1 is coupled to the R+ output of a phase selective detector unit (e.g., PSU 11 depicted in FIG. 4). The phase selective detector unit (PSU) will rectify AC currents (e.g., 524) received from a phase reference transformer (e.g., 525) and output unfiltered rectified DC currents (e.g., 191), also referred to as R+ currents or phase reference voltage, when the PSU 523/11 receives the aforementioned AC currents 524 input from the phase reference voltage transformer 525 depicted in FIG. 5, or phase reference voltage transformer 35 in FIG. 5A, or phase reference voltage transformer 45 in FIG. 5B. Phase voltage trigger relay K1 positive control pin 3 is coupled to wire pad 24 (FIG. 8), which is coupled to positive unfiltered R+ DC control currents (e.g., 191) from an R+ output of the phase selective detector unit (e.g., 523).

Phase Voltage Trigger relay K1 negative control pin 4 is coupled to wire pad 23 (FIG. 8) which is coupled to the phase selective detector unit's DC currents outputs common reference (R common terminal at pin TB6 in FIG. 4), herein referred to as the R currents. The phase selective detector unit 11/523, as depicted in FIG. 4, has R+ and R− output currents, both being positive DC output currents relative to the R common terminal.

Solid-state relay K1 positive control pin 3 is coupled to a first end of resistor R1. A second end of resistor R1 is coupled to K1 negative control pin 4. Resistor R1 serves as an impedance load matching resistor to allow for the electronic track relay 80 to present itself as having nearly the same loading effect to a phase selective detector unit (e.g., 523/11) as an electro-magnetic type track relay.

Additionally, solid-state relay K1 positive control pin 3 is coupled to a first end of transient voltage suppressor TVS diode D16. A second end of the TVS diode D16 is coupled to K1 negative control pin 4, thereby, affording transient voltage protection to the control pins of solid-state relay K1.

As depicted in FIG. 8, solid-state relay K1 positive DC currents output pin 2 is coupled to a first end of capacitor C6 in FIG. 8A, with a second end of capacitor C6 coupled to a ground reference, which is the negative output currents of DC-DC converter U1, herein, referred to as ground. Capacitor C6 serves as a currents smoothing capacitor to provide for near steady R+ DC currents to be coupled to micro-controller IC U2 pin 7. The output R+ and R currents from the phase selective detector unit 523/11 are unfiltered type DC currents coupled to control pins 3 and 4, respectively, of solid state relay K1, whereby, the dedicated DC output currents transmitted by pin 2 of the aforementioned solid-state relay K1 will not be of steady type DC currents coupled to pin 7 of micro-controller IC U2. Steady DC currents coupled to pin 7 of micro-controller IC U2 are preferred.

Additionally, in FIG. 8A, a first end of resistor R6 is coupled to pin 7 of micro-controller IC U2, with a second end of resistor R6 being coupled to the electronic track relay circuitry's ground. Resistor R6 ensures pin 7 of the micro-controller IC U2 is held at ground potential during the absence of any received DC currents.

In, yet, another aspect, solid-state relay K2 in FIGS. 8-8A corresponds to the track trigger relay 72 of FIG. 7. As depicted in FIG. 8, solid-state relay K2 is a track voltage trigger relay, whereas pin 1 of relay K2 is a positive DC currents input and pin 2 of K2 is a positive DC currents output. Pin 1 of relay K2 is coupled to positive output pin 6 of DC-DC converter U1 to receive dedicated positive DC currents. Pin 3 of the relay K2 is a positive control, whereas pin 4 is a negative control and is coupled to pin 7 of DC-DC converter U1 to receive dedicated negative currents. Pin 7 of DC-DC converter U1 serves as the electronic track relay circuitry's ground reference. When control currents are coupled to pin 3 and pin 4 of relay K2, pin 2 of the relay K2 will conduct positive output DC currents to a load.

Control pin 3 for track voltage trigger relay K2 is coupled to the R− output of a phase selective detector unit (e.g., PSU 11 depicted in Fig.). The phase selective detector unit (PSU) will rectify the coded AC currents (e.g., 195 or 595) received from a rail or rails of the track (e.g., first section of track rails 197) and output filtered rectified coded DC currents (e.g., 194), also referred to as R− currents or as track voltage, when the PSU 523/11 is receiving the aforementioned coded AC currents 195 from a rail or rails of the track coupled to the phase selective detector unit's track code input terminals via step up transformer depicted as 521 in FIG. 5, as 31 in FIG. 5A, or as 41 in FIG. 5B. Track voltage trigger relay K2 positive control pin 3 is coupled to wire pad 26 (FIG. 8) which is coupled to positive filtered R− DC control currents (e.g., 194) from an R− output of the phase selective detector unit (e.g., 523).

Track voltage trigger relay K2 negative control pin 4 is coupled to wire pad 25 (FIG. 8) which is coupled to the phase selective detector unit's DC currents outputs common reference(R common terminal at pin TB6 in FIG. 4), herein referred to as the R currents. The phase selective detector unit, as depicted in FIG. 4, has R+ and R− output currents, both being positive DC output currents relative to the R common terminal.

Solid-state relay K2 positive control pin 3 is coupled to a first end of resistor R15. A second end of resistor R15 is coupled to K2 negative control pin 4. Resistor R15 serves as an impedance load matching resistor to allow for the electronic track relay 80 to present itself as having nearly the same loading effect to a phase selective detector unit (e.g., 523/11) as an electro-magnetic type track relay.

Additionally, solid-state relay K2 positive control pin 3 is coupled to a first end of transient voltage suppressor TVS diode D15. A second end of the TVS diode D15 is coupled to K2 negative control pin 4, thereby, affording transient voltage protection to the control pins of solid-state relay K2.

As depicted in FIG. 8, solid-state relay K2 positive DC currents output pin 2 is coupled to pin 11 of micro-controller IC U2 depicted in FIG. 8A. The output R− and R currents from the phase selective detector unit are filtered rectified coded DC currents (e.g., 194) converted from the received coded AC track currents (e.g., 595/195) coupled from a rail or rails of a track (e.g., first section of track rails 197) to the phase selective detector unit. The filtered rectified coded DC currents (e.g., 194) are likely not of DC square wave type due to transmission distortion, and are coupled to control pins 3 and 4, respectively, of solid state relay K2. The dedicated DC output currents transmitted by pin 2 of the aforementioned solid-state relay K2 may incur an increase with the duty cycle's on-time % when compared to the coded AC track currents coupled to pin 11 of micro-controller IC U2. The increase with the duty cycle's on-time % may also be attributed as to how the control pins for solid-state relay K2 interprets the aforementioned R− coded pulses (e.g., 194) not being true square wave pulses, as well. However, micro-controller IC U2 in some embodiments are programmable or hardwired to allow for some adjustment to be made to the increases in duty cycle on-time %, to achieve a more favorable on-time %.

Additionally, in FIG. 8A, a first end of resistor R5 is coupled to pin 11 of micro-controller IC U2, with a second end of resistor R5 being coupled to the electronic track relay circuitry's ground. Resistor R5 ensures pin 11 of the micro-controller IC U2 is held at ground potential during the absence of any received DC currents.

Coded control currents (e.g., 194) transmitted from the R− and R terminals of the phase selective detector unit 11 depicted in FIG. 4 are coupled to pin 3 and pin 4 of relay K2, respectively, whereas pin 2 of the solid-state relay K2 will conduct coded dedicated positive output DC currents to micro-controller IC U2. As will be described in more detail herein, the micro-controller IC U2 in some embodiments is hardwired or programmable, whereas a check is made for the time duration of an energized state for micro-controller IC U2 pin 11. If the micro-controller IC U2 pin 11 is held high and exceeding a predetermined time, outputs currents for solid-state relays K3 and K4, being the Normally Open or Reverse (R) contacts, will be commanded to turn off, whereas, solid-state relays K5 and K6, being the Normally Closed or Normal (N) contacts, are commanded to conduct currents, and illuminate error LED D5 in a steady state.

The electronic track relay 80 in FIGS. 8 and 8A includes light emitting diode D5, which provides for a visual indication as to the types of signaling faults, such as, but not limited to, missing R+ currents (e.g., 191) or input AC currents (e.g., 524 and 595) being out of phase, as well as internal circuitry operational errors of the electronic track relay 80. An internal fault of the electronic track relay 80 would include any instances where magnetic-latching relays K7 and K8 were found to be out of correspondence as detected by micro-controller IC U2. Various flash rates, including steady state illumination, for the light emitting diode D5 conveys to railroad signaling personnel information as to the type of fault micro-controller IC U2 has detected, as well as providing for a warning indication for a broken rail condition. The aforementioned visual indications provided by light emitting diode D5 can serve as an aid to railroad signal personnel when routine signal system testing is performed, or, during investigations made by the railroad signal personnel when a railroad signal system is found to be in fault. The micro-controller U2 in some embodiments is hardwired or programmable for illuminating the error indicator LED D5 as will be described in more detail herein.

FIGS. 8 and 8A includes micro-controller U2 coupling sinking currents to light emitting diode (LED) D5 for illuminating the LED D5 in a steady state or in various flashing states. Micro-controller U2 pin 15 is coupled to a first end of a voltage dropping resistor within a single in-line package (SIP) resistor RN1 whereas a second end of the voltage dropping resistor is coupled to the dedicated positive output of DC-DC converter U1 pin 6. The first end of the voltage dropping resistor within SIP resistor RN1 is then coupled to opto-coupler U3 pin 2 being a negative control pin. Opto-coupler U3 pin 1 is a positive control pin coupled to a first end of a voltage dropping resistor within SIP resistor RN2 whereas a second end of the voltage dropping resistor coupled is to the dedicated positive output currents from DC-DC converter U1 pin 6. Opto-coupler IC U3 pin 16 is coupled to dedicated positive DC currents output from DC-DC converter U1. Opto-coupler IC U3 pin 15 is coupled to a first end of voltage drop resistor R10 whereas a second end of the resistor R10 is coupled to the anode end of LED D5. The cathode end of LED D5 is coupled to ground. When sink control currents are coupled to opto-coupler U3 pin 2 from micro-controller U2 pin 15, when an error has been detected, LED D5 will be illuminated in either a steady state or flashing at a pre-determined rate.

The circuit diagram 80 specifically illustrated FIG. 8 is for an electronic track relay installed within a GRS/Alstom AC Voltage Phase Selective type signaling system featuring B1 style plug-relays. Typically, steady V+ DC currents, being typically 12.8 VDC, will be available on either wire pad 32 or wire pad 34, depending on the type of signaling location.

FIG. 6 illustrates a configuration 60 into which the electronic track relay 80 has self-configured for ABS railroad territories. In the configuration 60 of FIG. 6, steady V+ DC currents are found on wire pad 32. Wire pad 32 is coupled to the V+ output of an external DC power source 20 illustrated in FIG. 3. Wire pad 34 functions as a coded V+ output as depicted in FIG. 6.

Specifically, in FIG. 6, magnetic latching relays K7 and K8 are depicted showing internal contact positions when the relays RESET coils receive driving currents, and the RESET contact positions configure the electronic track relay 80 for operational use within ABS type railroad signaling locations, being Master Locations and/or Cut Section Locations. Magnetic latching relays K7 and K8 then direct received V+ DC currents coupled from the railroad signaling system to the appropriate V+ input pin, i.e., pin 1 for solid-state relays K3, K4, and K5. Solid-state relay K6 is coupled directly to the railroad signaling system. Additionally, magnetic latching relays K7 and K8 also direct output V+ DC currents coupled to the railroad signaling system to the appropriate V+ output pin, i.e., pin 2 for solid-state relays K3, K4, and K5. The aforementioned solid-solid state relays function as Normally Closed and Normally Open relay contacts operating in Form C configuration for break before make contact operations. The aforementioned solid-state relay arrangements should not be construed in a limiting sense, as those having skill in the art can readily contemplate other circuit arrangements.

FIG. 6A illustrates a configuration 62 into which the electronic track relay 80 has self-configured for INT railroad territories. In the configuration 62 of FIG. 6A, for INT type signal locations, steady V+ DC currents will be found on wire pad 34. Wire pad 34 is coupled to the V+ output of an external DC power source 20 illustrated in FIG. 3. Wire pad 32 functions as a coded V+ output as depicted in FIG. 6A.

Specifically, in FIG. 6A, magnetic latching relays K7 and K8 are depicted showing internal contact positions when the relays SET coils receive driving currents, and the SET contact positions configure the electronic track relay 80 for operational use within INT type railroad signaling locations. Magnetic latching relays K7 and K8 then direct received V+ DC currents coupled from the railroad signaling system to the appropriate V+ input pin, i.e., pin 1, for solid-state relays K3, K4, K5, and K6. Additionally, magnetic latching relays K7 and K8 also direct output V+ DC currents coupled to the railroad signaling system to the appropriate V+ output pin, i.e., pin 2, for solid-state relays K3, K4, K5, and K6. The aforementioned solid-solid state relays function as the Normally Closed and Normally Open relay contacts operating in Form C configuration for break before make contact operations.

As illustrated in FIG. 8A, wire pad 34 is coupled to an anode of diode D1, relay K8 pin 10, and to opto-coupler U5 pin 3. Wire pad 32 is coupled to an anode of diode D2, relay K8 pin 12, and to opto-coupler U5 pin 1. A cathode of diode D1 is coupled to a cathode of diode D2. The aforementioned cathode junction comprised of diode D2 and diode D1 are coupled to DC-DC converter U1 pin 2 to provide V+ DC input currents for powering the DC-DC converter U1, and serve as a blocking currents diode providing for electrical isolation between wire pads 32 and 34. Uni-directional TVS diode D17 has an anode end connected to wire pad 21, whereas wire pad 21 is coupled to the V− output of an external DC power source 20 illustrated in FIG. 3 and is coupled to DC-DC converter U1 pin 7 providing for input power to the DC-DC converter U1.

The electronic track relay 80 in FIG. 8A includes dual channel opto-coupler IC U5 which corresponds to the opto-coupler circuit 76 of FIG. 7 and triggers the micro-controller IC U2 to determine the type of the signaling location the electronic track relay 80 has been installed within, based on the power supply scheme of the signaling location. The dual channel opto-coupler IC U5 has pin 1 coupled to wire pad 32 and pin 3 coupled to wire pad 34 for receiving steady V+ DC currents from external DC power source 20 illustrated in FIG. 3, allowing the electronic track relay 80 to determine the type of signaling location, being ABS or INT, the electronic track relay 80 has been installed within. Opto-coupler IC U5 will then transmit dedicated DC currents to the appropriate micro-controller IC U2 pin to begin the electronic track relay's automatic self configuration process described herein below with respect to FIG. 9J.

Opto-coupler IC U5 pin 2 is coupled to a first end of a voltage dropping resistor within SIP resistor RN5, whereas a second end of the voltage dropping resistor is coupled to wire pad 21 for receiving V− DC currents from external DC power source 20 illustrated in FIG. 3. Opto-coupler IC U5 pin 4 is coupled to a first end of, yet, another voltage dropping resistor within SIP resistor RN5, whereas a second end of the voltage dropping resistor is coupled to wire pad 21 for receiving V− DC currents from the external DC power source 20 illustrated in FIG. 3. Opto-coupler IC U5 pin 6 is coupled to pin 8, which is coupled to dedicated DC positive currents output of DC-DC converter U1 pin 6.

Upon connecting the electronic track relay 80 to a railroad signal system, e.g., an ABS signaling location as illustrated in FIG. 6, steady DC V+ currents, being typically 12.8 VDC, are present on wire pad 32, whereas wire pad 34 is a V+ output from the electronic track relay 80 coupled to the ABS railroad signal system.

FIG. 6A illustrates the V+ inputs and V+ outputs coupled between the electronic track relay 80 and an INT type railroad signal location, in which steady DC V+ currents, being typically 12.8 VDC, are present on wire pad 34, whereas wire pad 32 is a V+ output from the electronic track relay 80 coupled to the INT railroad signal system.

The situation involving an ABS signal location will be now described. When opto-coupler IC U5 pin 1 is found receiving V+ currents from wire pad 32, opto-coupler IC U5 pin 7 transmits dedicated DC currents coupled from DC-DC converter U1 pin 6 to a first end of resistor R4 having a second end coupled to ground, and to micro-controller IC U2 pin 16, whereas micro-controller IC U2 initiates its Main programming routines (FIG. 9J) and determines that the electronic track relay has been installed in an ABS signal location.

As micro-controller IC U2 loops through its Main programming routines (FIG. 9J), and the decision has been made by micro-controller U2 that the electronic track relay 80 has been installed within an ABS type signaling location, micro-controller IC U2 pin 13 transmits sinking currents to solid-state relay IC U4 pin 4, being a negative control pin. Solid-state relay IC U4 pin 3 is a positive control pin coupled to a first end of a voltage dropping resistor within SIP resistor RN4 whereas a second end of the voltage dropping resistor is coupled to the dedicated positive output currents of DC-DC converter U1 pin 6. Solid-state relay IC U4 pin 6 is coupled to dedicated positive DC output currents from DC-DC converter U1, whereby solid-state relay IC U4 pin 5 outputs dedicated positive drive currents coupled from DC-DC converter U1 pin 6 to magnetic-latching relay K7 pin 2 which is a first end of the RESET coil for the magnetic-latching relay K7. Magnetic-latching relay K7 pin 2 is also serially coupled to magnetic-latching relay K8 pin 2, which is the RESET coil for the magnetic-latching relay K8, whereby the RESET coils for magnetic-latching relays K7 and K8 operate in unison. Magnetic-latching relay K7 pin 2 is coupled to the cathode end of diode D3 which has the anode end coupled to ground. The diode D3 provides for the shunting of transient EMF currents to ground when the aforementioned RESET coil(s) become de-energized. Resistor R4 holds micro-controller IC U2 pin 13 to ground potential when the pin 13 is not transmitting drive currents to magnetic-latching relay K7 pin 2, when the electronic track relay 80 is not operating in the ABS configuration (FIG. 6). The solid-state relay IC U4 in FIGS. 8-8A corresponds to dual output solid-state relay 700 of FIG. 7.

The situation involving an INT signal location will be now described. When opto-coupler IC U5 pin 3 is found receiving V+ currents from wire pad 34, opto-coupler IC U5 pin 5 transmits a signal to micro-controller IC U2 pin 17, whereas micro-controller IC U2 initiates its Main programming routines (FIG. 9J) and determines that the electronic track relay has been installed in an INT signal location.

As micro-controller IC U2 loops through its Main programming routines (FIG. 9J), and the decision has been made by micro-controller U2 that the electronic track relay 80 has been installed within an INT type signaling location, micro-controller IC U2 pin 8 transmits sinking currents to solid-state relay IC U4 pin 2, being a negative control pin. Solid-state relay IC U4 pin 1 is a positive control pin coupled to a first end of a voltage dropping resistor within SIP resistor RN4 whereas a second end of the voltage dropping resistor is coupled to the dedicated positive output currents of DC-DC converter U1 pin 6. Solid-state relay IC U4 pin 8 is coupled to dedicated positive DC output currents from DC-DC converter U1, whereby solid-state relay IC U4 pin 7 outputs dedicated positive drive currents coupled from DC-DC converter U1 pin 6 to magnetic-latching relay K7 pin 1, which is a first end of the SET coil for the magnetic-latching relay K7. Magnetic-latching relay K7 pin 1 is also serially coupled to magnetic-latching relay K8 pin 1, which is the SET coil for the magnetic-latching relay K8, whereby the SET coils for magnetic-latching relays K7 and K8 operate in unison. Magnetic-latching relay K7 pin 1 is coupled to the cathode end of diode D4 which has the anode end coupled to ground. The diode D4 provides for the shunting of transient EMF currents to ground when the aforementioned SET coil(s) become de-energized. Resistor R3 holds micro-controller IC U2 pin 17 to ground potential when the pin 17 is not transmitting drive currents to magnetic-latching relay K7 pin 2, when the electronic track relay 80 is not operating in the INT configuration (FIG. 6A).

The electronic track relay 80 in FIG. 8A includes the interconnections made between the contacts of magnetic-latching relays K7 and K8 for properly routing V+ DC input currents (e.g., 194) received from a railroad signal system (e.g., first section of track rails 197) to the correct V+ input pin, being pin 1, for solid-state relays K3, K4, K5, and K6 emulating Normally Closed and Normally Open relay contacts. The magnetic-latching relays K7 and K8 also properly routes V+ DC output currents (e.g., 593) from pin 2 of the aforementioned K3, K4, K5, and K6 solid-state relays to be transmitted to the railroad signal system (e.g., second section of track rails 198), whereas the aforementioned V+ DC currents (e.g., 593) are the positive DC currents coupled to the electronic track relay 80 from the main DC power source found within the railroad signaling location in which the electronic track relay 80 is installed.

In some embodiments, the aforementioned solid-state relays found within the electronic track relay 80 comprises two independent SPDT relay contact sets. On the one hand, solid-state relay K6 functions as a Normally Closed contact or as the N contact in railroad signaling terminology, and solid-state relay K4 functions as a Normally Open contact or as the R contact in railroad signaling terminology. Solid-state relays K6 and K4 comprise an independent SPDT relay contact set having pre-set time delayed control pin operations provided by micro-controller IC U2 to ensure Form C, break before make, type contact operations. On the other hand, solid-state relay K5 functions as a Normally Closed contact or as the N contact in railroad signaling terminology, and solid-state relay K3 functions as a Normally Open contact or as the R contact in railroad signaling terminology. Solid-state relays K5 and K3 comprise a second independent SPDT relay contact set having pre-set time delayed control pin operations provided by micro-controller IC U2 to ensure Form C, break before make, type contact operations.

The interconnections made between the aforementioned magnetic-latching relays K7 and K8, and with the aforementioned solid-state relays K3, K4, K5, and K6 as exemplarily depicted in FIGS. 8 and 8A pertain to an electronic track relay operating within a GRS/Alstom AC Voltage Phase Selective Cab Code Signal System in accordance with some embodiments. However, electronic track relays in accordance with further embodiments have capabilities to function in various railroad signaling applications.

During the normal course of operations for the electronic track relay 80, micro-controller IC U2 continuously transmits sink currents in approximate 18 mSec (0.018 seconds) intervals to perform status checks for magnetic-latching relays K7 and K8 to ensure both aforementioned relays remain in correspondence. The reason is that railroad signaling locations found near the railroad tracks may become subjected to the vibrations caused by passing trains. The degree of the vibrations can vary based on the size of the signal location's housing, whereas some signaling locations can be only small cabinets. The distance from the tracks where the aforementioned signal location housings are placed from the railroad tracks is, yet, another factor determining the degree of vibrations from passing trains the signaling equipment located within the signal housings will be subjected to. For a typical cab code type signaling system, the coded AC currents coupled to a rail or rails of the track, any change with the status of the coded AC currents will not be conveyed to the operator of a train until 3 seconds in time have lapsed, whereas, 3 seconds is the typical time duration required for the train's on-board cab signal system to decipher the received coded AC pulses coupled from a signal location to a rail or rails of the track. Therefore, should the magnetic-latching relays K7 and K8 were found to be out of correspondence, the out of correspondence condition would be corrected, in some embodiments, within a time span of less than 3 seconds so as to not unnecessarily disrupt the normal operations of the railroad signal system. For an out of correspondence condition, micro-controller IC U2 will transmit sink currents to the appropriate coil(s) within approximately 18 mSec (0.018 seconds) to restore magnetic-latching relays K7 and K8 into their proper positions.

When the electronic track relay 80 has self-configured for operations within an ABS type railroad signaling location (FIG. 6), a check path is established from micro-controller IC U2, whereas sink currents are transmitted from U2 pin 13 having a serial connection through each magnetic latching relay K7 and K8, and then returns back to U2 pin 6. As micro-controller IC U2 pin 13 couples sink currents to magnetic-latching relay K7 pin 6, the sink currents then loops through the circuitry as follows: K7 pin 6 coupled to K7 pin 4, K7 pin 4 coupled to K8 pin 4, K8 pin 4 coupled to K8 pin 6 which is coupled U2 pin 6 to complete the check loop. Should the check loop be found disrupted, micro-controller IC U2 pin 13 will transmit within approximately 18 mSec (0.018 seconds) restoring sink currents to the RESET coils of both magnetic-latching relays, i.e., to K7 pin 2 and K8 pin 2.

When the electronic track relay 80 has self-configured for operations within an INT type railroad signaling location (FIG. 6A), a check path is established from micro-controller IC U2, whereas sink currents are transmitted from U2 pin 8 having a serial connection through each magnetic latching relay K7 and K8, and then returns back to U2 pin 3. As micro-controller IC U2 pin 8 couples sink currents to magnetic-latching relay K7 pin 8, the sink currents then loops through the circuitry as follows: K7 pin 8 coupled to K7 pin 4, K7 pin 4 coupled to K8 pin 4, K8 pin 4 coupled to K8 pin 8 which is coupled U2 pin 3 to complete the check loop. Should the check loop be found disrupted, micro-controller IC U2 pin 8 will transmit within approximately 18 mSec (0.018 seconds) restoring sink currents to the SET coils of both magnetic-latching relays, i.e., to K7 pin 1 and K8 pin 1.

FIG. 9 through 9J are flow charts for the operations (by programming or hard-wiring) for micro-controller IC 74 depicted in FIG. 7. In some embodiments, the operations of micro-controller IC 74 are implemented by appropriately programming the micro-controller IC U2 of FIG. 8A. The description below will be given with respect to the electronic track relay 80.

FIG. 9J is the flow char of the Main programming routine which runs when the electronic track relay 80 is initialized, i.e., when the electronic track relay 80 is just plugged into a signal house at a signaling location and powered up. At startup process 9038, all inputs and outputs (I/O) are initially set high, whereas no drive currents are coupled to opto-coupler 78/83. Thus, no output currents are generated by solid-state relays K3, K4, K5, K6. Memory locations in an internal memory of micro-controller IC U2 are initialized for use as flags for future use.

At process 9040, a check is made to determine the proper type of installation of the TR relay 80, i.e., whether the electronic track relay 80 is in an ABS or an INT location. The determination is performed, as discussed above, by detecting the presence or absence of a steady, predetermined voltage (e.g., 12.8 VDC) at an appropriate wire pad, e.g., wire pad 32 or wire pad 34, depending on the type of signaling location. The presence of a steady V+ DC voltage (e.g., 12.8 VDC) on wire pad 32 indicates that the electronic track relay 80 has been installed in an ABS signaling location. The presence of a steady V+ DC voltage (e.g., 12.8 VDC) on wire pad 34 indicates that the electronic track relay 80 has been installed in an INT signaling location.

If it is determined to be an ABS installation, at process 9044, memory flags are set accordingly to be referred to at a latter time, and K7 and K8 are switched to the position of Reset for use in the ABS mode (FIG. 6).

If it is determined to be an INT installation, at process 9042, memory flags are set accordingly to be referred to at a latter time, and K7 and K8 are switched to the position of Set for use in the INT mode (FIG. 6).

At process 9046, a check is preformed to verify conformance of settings of K7 and K8 by calling subroutine 9E.

At process 9048, a check is made to determine if the R− signal (Track) is in a HIGH (on) state or in a LOW (off) state. If it is found that the R− signal is in a HIGH (on) state, at process 9052, a memory location is flagged to reflect this status. If it is found that the R− signal is in a LOW (off) state, at process 9050, a memory location is flagged to reflect this status.

At process 9054, subroutine 9A is called to perform a test of the R+ signal to determine its state.

At processes, 9056, 9058, the R− signal is outputted to U2 pin 11 from K2 pin 2.

At process 9060, yet another check is made to determine the status of the R− signal at U2 pin 11 from the information received from K2 pin 2 to determine if it is a HIGH (on) state or a LOW (off) state. If it is found that the R− signal is in a HIGH (on) state, the process then proceeds, at process 9062, to subroutine 9H (R− Present). If it is found that the R− signal is in a LOW (off) state, the process then proceeds, at process 9064, to subroutine 91 (R− Not present).

FIG. 9H is the flow char of the subroutine 9H (R− Present).

At process 992 of subroutine 9H, a memory location is set to reflect the process has entered subroutine 9H and resets all internal counters of micro-controller IC U2 used in this subroutine 9H.

At process 994, a check is made to determine if an AC voltages counter on the R− signal has expired. If it is determined that the AC voltages counter has not expired (non-zero), which indicates that the AC coded track currents (R− signal) are in a reversed phase order, the process is then sent, at process 9014, to subroutine 9G (AC currents out of phase) and then proceeds to process 9016 to determine if the R− signal is still present. If it is determined that the R− signal is present, the process is returned to process 992. If the R− signal is not present, the process then returns to process 9060 of the Main program 9J to determine again whether the subroutine 9H or 91 is to be called.

If it is determined at process 994 that the AC voltages counter has expired (zero), which indicates that the phase of the AC coded track currents (R− signal) is proper, at process 996, drive currents are removed from U2 pin 12 to U3 pin 8 to turn off K3 and K4.

At process 998, a delay, e.g., of 200-400 micro seconds (μs), is performed. The purpose of this delay is to ensure that the SSRs K3 and K4, which are the Normally Open or Reverse (R) contacts, are turned off before the SSRs K5 and K6, which are the Normally Closed or Normal (N) contacts, are turned on in the subsequent process 9000. Thus, Form C break before make relay contact operations are ensured. The time delay is selected based on the response time of the particular SSR used as K3 and K4. For example, for an SSR of a 300 μs response time, the delay in process 998 is set to be greater than such response time, e.g., at 400 μs.

At process 9000, drive currents are output from U2 pin 14 to U3 pin 4 to turn on K5 and K6.

At process 9002, a check is made to verify the status of K5 and K6 insuring that the drive currents outputted at process 9000 were successful in turning K5 and K6 on.

At process 9004, subroutine 9A is called to check the Phase status, i.e., the status of the R+ signal.

At process 9006, subroutine 9E is called to check the positions of K7 and K8 configuration.

At process 9008, subroutine 9D is called to refresh K7 and K8 insuring proper positions of K7 and K8.

At process 9010, subroutine 9 is called to check if the R− signal (Track) was present for longer than required.

At process 9012, a check is made of the Track status, i.e., whether the R− signal is HIGH or LOW. If it is determined that the R− signal is HIGH (on), the process returns to process 9002. If it is determined that the R− signal is LOW (off), the process is returned to process 9060 of the Main program 9J to determine again whether the subroutine 9H or 91 is to be called.

If, at process 9060, it is determined that the R− signal is LOW (off), subroutine 91 is called.

FIG. 91 is the flow char of the subroutine 91 (R− Not Present).

At process 9018, a memory location is set to reflect the process has entered subroutine 91 and resets all internal counters of micro-controller IC U2 used in this subroutine 91.

At process 9020, drive currents are removed from U3 pin 14 to U3 pin 4 to turn off K5 and K6.

At process 9022, a delay, e.g., of 200-400 micro seconds, is performed. The purpose of this delay is similar to that discussed with respect to process 998 in the subroutine 9H.

At process 9024, drive currents are outputted from U2 pin 12 to U3 pin 8 to turn on K3 and K4.

At process 9026, a check is made of K3 and K4 to insure that K3, K4 were turned on.

At process 9028, subroutine 9A is called to check the Phase status, i.e., the status of the R+ signal.

At process 9030, subroutine 9B is called to check lock up conditions.

At process 9032, subroutine 9D is called to refresh K7 and K8.

At process 9034, subroutine 9E is called to check positions of K7 and K8.

At process 9036, a check is made of the Track status, i.e., whether the R− signal is HIGH or LOW. If it is determined that the R− signal is LOW (off), the process is returned to process 9026. If it is determined that the R− signal is HIGH (on), the process is returned to process 9060 of the Main program 9J to determine again whether the subroutine 9H or 91 is to be called.

FIG. 9 is the flow chart of the subroutine 9 (R− Active Too Long).

Subroutine 9 determines if the R− signal was active longer than required. At processes 90, 92, the R− signal is outputted from K2 pin 2 to U2 pin 11. The R− signal is counted by process 94. At process 96, if it is determined that the counter did not exceed the pre-determined amount, the process is returned to where it came from. If it is found at process 96 that the counter was exceeded, at process 98, drive currents from U2 pin 12 is removed from U3 pin 3, thereby turning off K3 and K4 and drive currents from U2 pin 15 coupled with U3 pin 2 turn on error LED D5.

At process 900, a delay, e.g., of approximate 2-4 millisecond (2-4 ms) is performed. The purpose of this delay is similar to that discussed with respect to process 998 in the subroutine 9H.

At process 902, drive currents are output from U2 pin 14 to U3 pin 4 to turn on K5 and K6.

At process 904, a check is made of the Track status, i.e., whether the R− signal is HIGH or LOW. If it is determined that the R− signal is LOW (off), the process returns to where it was called from. If it is determined that the R− signal is High (on), then the process returns to process 98.

FIG. 9A is the flow char of the subroutine 9A (Phase R+ Check).

At processes 906, 908, the R+ signal is outputted from K1 pin 2 to U2 pin 7.

At process 910, U2 pin 7 is checked for the R+ signal transmitted from K1 pin 2 to see if the R+ signal is LOW (off) or HIGH (on). If it is determined that the R+ signal was HIGH (on), then, at process 912, a memory location is flagged accordingly to indicate the absence of a lock-up condition. The process is then returned to where it was called from.

If it is determined at process 910 that the R+ signal is LOW (off), at process 914, the same memory location as that in process 912 is flagged accordingly to indicate the presence of a lock-up condition.

At process 916, a check is made to determine if the R+ signal was LOW (off) longer than required. If it is determined that the R+ signal was not LOW (off) for a long period, the process returns to where it is called from. If it is determined that the R+ signal was LOW (off) for a set period of time, another memory location is flagged to reflect the current status.

FIG. 9B is the flow char of the subroutine 9B (Lock up Check).

At process 920, a check is made to determine if the memory location set in process 912/914 was flagged (process 914) to indicate a lock up condition. If is determined that there was no flag then process returns to where it was called from.

If it is determined that the memory location was flagged to indicate a lock up condition, process 922 determines if the Normal contacts or Reverse contacts were active at the time.

If it is determined at process 922 that the Reverse contacts were active, process 924 turns off drive currents of U2 pin 12 and U3 pin 8, thereby turning off K3 and K4. Drive currents are turned on at U2 pin 14 to U3 pin 4, thereby turning on K5 and K6.

At process 926, subroutine 9A is called to check the Phase R+ status.

At process 928, subroutine 9D is called to refresh K7 and K8.

At process 930, subroutine 9E is called to check proper configuration of K7 and K8.

At process 932, it is determined if the R− signal's status changed, i.e., whether the R− signal has changed from Low to High or not. If it is determined that the R− signal's status did not change, i.e., the R− signal remains Low, process 934 calls subroutine 9A to check the Phase R+ signal status.

At process 936, a check is made to determine if a lock up condition is still present, i.e., if the memory location is still flagged to indicate a lock up condition. If it is determined that a lock up condition is still present, the process returns to process 924.

If it is determined that a lock up condition is no longer present, at process 938, drive currents are removed from U2 pin 15 and U3 pin 2, thereby turning off error LED D5. Drive currents are removed from U2 pin 12 to U3 pin 8, thereby turning off K3 and K4. Drive currents are turned on at U2 pin 14 and U2 pin 4, thereby turning on K5 and K6. The process is returned to where it was called from.

At process 932, if it was determined that the R− signal's status changed, i.e., the R− signal has changed from Low to High, the process proceeds to process 940. At process 940, drive currents from U2 pin 14 to U3 pin 4 are removed, thereby turning off K5 and K6. Drive currents are turned on from U2 pin 12 to U3 pin 8, thereby turning on K3 and K4.

At process 942, subroutine 9A is called to check Phase R+ status.

At process 944, subroutine 9D is called to refresh K7 and K8.

At process 946, subroutine 9E is called to check relays K7 and K8 configuration.

At process 948, subroutine 9A is called to determine Phase R+ status.

At process 950, a check is made to determine if a lock up condition is still present, i.e., if the memory location is still flagged to indicate a lock up condition.

If it is determined at process 950 that a lock up condition is no longer present, at process 952, drive currents are removed from U2 pin 15 to U3 pin 2 to turn off error LED D5. Drive currents are removed from U2 pin 14 to U3 pin 4, thereby turning off K5 and K6. Drive currents are turned on from U2 pin 12 to U3 pin 8, thereby turning on K3 and K4. The process is then returned to where it was called from.

If it is determined at process 950 that a lock up condition is still present, the process returns to process 940.

FIG. 9C is the flow char of the subroutine 9C (Phase Voltage R+ Loss Indication).

Process 954 retrieves from the internal memory of the micro-controller IC U2 the R+ signal timer/counter information. This timer/counter was initially set (when the electronic track relay was powered up) to reflect the maximum number of times (e.g., 5) the R+ signal is determined as being lost or shaky before the electronic track relay outputs an alarm, e.g., by flashing error LED D5 at 30 ppm.

If it is determined at process 956 that the timer did not expire, i.e., the R+ signal has not been lost/shaky 5 times, process 958 decrements the timer and stores a new count (e.g., for the first time the R+ signal is lost/shaky, the counter decrements from 5 to 4). The process then returns to where it was called from.

If it was determined at process 956 that the timer did expire, i.e., the R+ signal has been lost/shaky 5 times, process 960 flashes Error LED D5 and restores the timer's count to a pre-determined value, e.g., 5. The process then returns to where it was called from.

FIG. 9D is the flow char of the subroutine 9D (K7 and K8 Refreshing).

Subroutine 9D refresh K7 and K8 relays, whereas a determination, at process 962, is made for either an ABS or an INT configuration mode. If the INT configuration is detected, at process 964, drive currents from U2 pin 8 coupled to U4 pin 2 refresh currents are transmitted to SET coil for relays K7 and K8.

If a determination, at process 962, is made that the electronic track relay has been installed within an ABS type railroad signal location, at process 968, sink currents are coupled from U2 pin 13 to U3 pin 4 to refresh relays K7 and K8 RESET coils.

At process 966, subroutine 9F is called to confirm that K7 and K8 internal contacts are correct for the INT mode. The process then returns to where it is called from.

FIG. 9E is the flow char of the subroutine 9E (K7 and K8 Configuration Check).

Subroutine 9E check relays K7 and K8 for proper configuration. At process 970, a check is made to determine if K7 and K8 are in proper configuration for the signaling location/house in which the TR relay 80 is located. If it is determined that it is correct, the process returns to where it was called from.

If it is determined that it is in the incorrect, at process 972, all drive currents from U2 to U3 for driving K3, K4, K5, and K6 are turned off. Drive currents from U2 pin 15 are coupled to U3 pin 2, thereby turning on the error LED D5.

At process 974, subroutine 9D is called to refresh relays K7 and K8.

At process 976, a check is made to determine if the update (refreshing) was successful. If a determination confirms that the update was successful, at process 978, drive currents coupled from U2 pin 15 to U3 pin 2 are removed, thereby turning off error LED D5. The process is returned to where it was called from.

If it was determined at process 976 that the update was not successful, the process returns to process 970.

FIG. 9F is the flow char of the subroutine 9F (Confirming K7 and K8 Position).

Subroutine 9F confirms positions of K7 and K8. At process 980, a check is made in the internal memory of the micro-controller IC U2 to determine if the TR relay 80 is in either ABS or INT mode.

If a determination is made for the INT mode, at process 982, another check is made by U2 pin 8 transmitting currents through K7 and K8 serial contacts to verify K7 and K8 positions, whereby the transmitted currents from U2 pin 8 are coupled to U2 pin 3. If it is determined at process 982 that K7 and K8 are in correspondence (proper position), then the process returns to where it was called from.

If it is determined at process 982 that K7 and K8 are out of correspondence, then subroutine 9E is called at process 984. The process returns to where it was called from.

At process 980, if a determination is made for the ABS mode, then another check is performed at process 986 by coupling output currents from U2 pin 13 through K7 and K8 serial contacts to verify K7 and K8 positions by coupling said transmitted currents from U2 pin 13 to U2 pin 6. If a determination is made at process 986 that K7 and K8 are in correspondence, then the process returns to where it was called from.

If a determination is made at process 986 that K7 and K8 are out of correspondence, then subroutine 9E is called at process 984. The process then returns to where it was called from.

FIG. 9G is the flow char of the subroutine 9G (AC Voltages Out of Phase).

Subroutine 9G is called when AC currents are determined to be out of phase. At process 988, drive currents coupled from U2 pin 14 to U3 pin 4 are terminated, thus terminating output currents transmitted by K5 and K6. Drive currents are transmitted by U2 pin 12 and are coupled to U3 pin 8, whereby output currents are coupled to K3 and K4. At process 990, drive currents are coupled from U2 pin 15 to LED D5 in a pulsed state. The process then returns to where it was called from.

It should be noted from the above description that R+ phase currents check subroutine 9A programs micro-controller IC U2 to ensure pin 7 of the micro-controller IC U2 is receiving R+ currents coupled from output pin 2 of solid-state relay K1. Upon the loss of R+ currents as determined by the aforementioned subroutine 9A, Lock up Check subroutine 9B will command the turnoff and turning on of output currents for the appropriate solid-state relays emulating the electronic track relay 80's Normally Closed and Normally Open relay contacts. Further, Phase Voltage R+ Loss Indication subroutine 9C will flash error LED D5 at an approximate rate of 30 flashes per minute (ppm) for providing railroad signaling personnel with a visual indicator dedicated to loss of received R+ currents (e.g., 191) by the electronic track relay 80.

In some embodiments, upon installation within a railroad signal location, the electronic track relay will self configure for either ABS or INT operations. In one or more embodiments, micro-controller integrated circuit U2 performed its signal location type identification sub-routine in a time span of approximately 0.5 seconds.

In some embodiments, visual indicators are also incorporated into the electronic track relay, eg by means of light emitting diodes (LEDs) to provide verification to railroad signal personnel as to which mode, ABS or INT, the electronic track relay has self configured in. For example, light emitting diode D7 provides for a visual indication that the electronic track relay has self configured for ABS signaling applications. Sink controlling currents are transmitted from micro-controller IC U2 pin 19 coupled to a cathode of light emitting diode D7 which has the anode coupled to a first end of voltage drop resistor R12, with a second end of drop resistor R12 coupled to ground. Light emitting diode D6 provides for a visual indication that the electronic track relay has self configured for INT signaling applications. Sink controlling currents are transmitted from micro-controller IC U2 pin 18 coupled to a cathode of light emitting diode D6, which has the anode coupled to a first end of voltage drop resistor R11, with a second end of drop resistor R11 coupled to ground.

In some embodiments, the electronic track relay also provides for continuous status checks for relays K7 and K8 to ensure both relays are in correspondence and remain set in their proper positions for ABS or INT modes via feedback loop currents generated by and received by micro-controller integrated circuit U2. Additionally or alternatively, micro-controller integrated circuit U2 periodically commands driving currents to be coupled to the appropriate coils of K7 and K8, whereas the SET coils are for INT mode operations and the RESET coils are for ABS operation, ensuring that vibrations from passing trains transmitted to the railroad signal location housing or wayside equipment cabinets have not placed the internal contacts of relays K7 and K8 out of correspondence. In the event micro-controller U2 detects the contact sets of K7 and K8 have become out of correspondence, drive currents are then transmitted to the appropriate SET or RESET coils of the aforementioned K7 and K8 relays to return the relays into correspondence before adverse effects are caused to the railroad signal system, whereby, causing unnecessary train movement delays.

In some embodiments, the electronic track relay also monitors the operational status of the Phase Reference Voltage (R+) currents coupled from the Phase Selective Detector Unit (PSU) to ensure the R+ currents are continuously received and to respond accordingly should the R+ currents become interrupted when track code R− currents are or are not being received.

For railroads operating with a signal system to govern the movements of trains, sections of railroad tracks of a defined distance, typically, one mile, are isolated from one another by means of rail insulated joints (e.g., 196) to create, in railroad terminology, what are known as signal blocks. As an example, for the AC Phase Selective Cab Code type railroad signal system utilized on electrified railroads, typically, the track wire pair utilized for coupling the AC coded currents transmitted from a signal location are connected to the rails of the track in a manner, where, the hot side of the AC coded currents are coupled to one rail of the track, and, the neutral side of the AC coded currents is coupled to the opposite rail. When insulated rail joints (e.g., 196) are encountered along the railroad track, on the opposite side of the insulated rail joints, the track wires carrying the coded AC currents output from a code follower relay (e.g., 137) will then be coupled to the rails of the railroad track in a reversed Phase order. To ensure the phase of the AC coded track currents are connected properly to the rails of a track, a comparison is made by the phase selective detector unit (PSU) between the phase of the received coded AC track currents (e.g., 595) to the phase of the reference AC currents (e.g., 524) received from a phase reference transformer (e.g., 525) being coupled to a second PSU input. If the AC track coded currents (e.g., 595) are found to be out of phase with those of the phase reference transformer AC currents (e.g., 524), the electronic track relay in accordance with some embodiments will respond in the same manner as its electro-magnetic latching track relay counterpart, i.e., will cease any coding operations and will lock onto its Normally Closed contacts.

In some embodiments, during instances when phase reference voltage currents (R+ ) (e.g., 191) are not being received by the electronic track relay, light emitting diode D5 will flash at a dedicated rate of approximately 30 pulses per minute (ppm) for alerting railroad signal personnel with a visual error indication being specific to the loss of R+ currents (e.g., 191).

In some embodiments, light emitting diode D5 is to flash at a dedicated rate of approximately 500 pulses per minute (ppm) for alerting railroad signal personnel with a visual error indication being specific to an internal error that has occurred within the electronic track relay's internal circuitry, for example, but not limited to, relays K7 and K8 being out of correspondence, thus, prompting railroad signal personnel to perform a reset action to the electronic track relay. In one or more embodiments, the reset action is a matter of momentarily removing the V+ or V− input DC currents to momentarily power down the electronic track relay's electronic circuitry, and then to re-power the electronic circuitry of the electronic track relay.

In some embodiments, the electronic track relay provides for the detection of broken rail conditions, and responds in its most restrictive manner by providing only output currents in a steady state from its Normally Closed (NC) contacts during the broken rail event, so as to not provide for a favorable signal to be conveyed to a train operating on the track having a broken rail condition. In addition, the electronic track relay also conveys the most restrictive form of output currents coupled to the other signal system components as well as to the other adjacent signal locations located on the same track. “Broken rail conditions” as used herein refer to a specific testing procedure where coded signals at a very high code rate, i.e., higher than the highest code rate (e.g., 420 beats per minute) used during normal operations. The electronic track relay is sufficiently sensitive to detect and react to such high code rates, e.g., higher than 420 beats per minute), and when high code rates are detected, the electronic track relay is locked out, providing for only steady output currents to be transmitted from its Normally Closed (NC) contacts and issuing an indication of fault via a steadily lit LED D5.

In some embodiments, light emitting diode (LED) D5 is to provide for a varying flash rate in intensity and rate determined by the severity of a near broken rail or broken rail condition, thereby providing for a visual indicator for alerting railroad signal personnel to the rail fault condition(s). For severe broken rail conditions detected by the electronic track relay, light emitting diode (LED) D5 will then be lit in a steady state indicating that the electronic Track Relay has locked out, providing for only steady output currents to be transmitted from its Normally Closed (NC) contacts, in a manner found to be consistent with the operation of electro-magnetic latching track relays subjected to same the same broken rail conditions.

In some embodiments, by means of program line codes within the micro-controller integrated circuit U2 of the electronic track relay, the electronic track relay is capable of compensating for some increases incurred to the duty cycle of the phase selective detector unit's R− output coded DC currents (e.g., 194) when coded AC currents (e.g., 595) coupled from the rail or rails of a railroad track to the phase selective detector unit (PSU) is then converted to low voltage DC coded currents (R− voltage) (e.g., 194). The increases with the duty cycle's on-time percent can be attributed to the filtering components utilized within the phase selective detector unit's DC coded output section, whereas the coded R− currents (e.g., 194) are not a true form of DC square wave type currents. The PSU low voltage R− coded DC output currents (e.g., 194) are then coupled to a coil of an electro-magnetic code follower relay or to a control terminal of an electronic track relay, whereas the code follower relay will then transmit coded AC currents (e.g., 192) to the rail or rails of a railroad track at the same code rate and duty cycle received from the aforementioned phase selective detector unit's coded DC currents output (R−) (e.g., 194) for the purpose of conveying track conditions to the driver of a train and to provide track condition information to other adjacent signal locations.

For electro-magnetic and electro-magnetic latching relays utilized in the coding of DC currents and AC currents, over time with use, such relays suffer from worn mechanical moving parts, decrease in magnetic coil flux fields, and burnt contacts due to electrical arc currents. The electronic track relay in accordance with some embodiments, being an electronic latching relay, overcomes some or most of the shortfalls of its electro-magnetic latching relay counterpart by means of having no moving parts that can become worn, and, having a plurality of solid-state relays to emulate relay contacts cannot suffer from burnt contact conditions when receiving electrical currents from a railroad signal system, or, when transmitting electrical currents to the railroad signal system and/or a rail or rails of a railroad track.

Similar to the electronic code follower relay disclosed in U.S. Pat. No. 7,357,359, by selecting DC current output solid-state relays (SSRs) having MOSFET output stages to emulate the contact sets found within electro-magnetic and electro-magnetic latching relays, the electronic track relay in accordance with some embodiments ensures DC currents coupled to the electronic track relay as input currents are transmitted as output currents having minimal voltage losses when the output currents are coupled to various signal system apparatuses.

Furthermore, an electronic version of a track relay or electronic latching relay in accordance with some embodiments is made compatible with a railroad's existing signal system, as well as requiring minimal labor for installation purposes by railroad signal personnel.

Furthermore, an electronic version of a track relay or an electronic version of a magnetic latching relay in accordance with some embodiments, being so configured to serve as a “plug and play” type device, allows for easy interchanges to be made. Thus, the electronic version of an electro-magnetic latching relay type track relay and/or an electronic latching relay in accordance with some embodiments may be easily substituted for its electro-magnetic latching relays and/or electro-magnetic type track relay counterparts, especially, for those railroads utilizing rack mounted plug-in style relays within their signal system. In addition, electro-magnetic latching relays or magnetic latching type track relays may be easily substituted for electronic type latching relays or electronic type track relays if a downgrade is necessary, e.g., due to maintenance.

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the TR relay is at Rest with Phase Voltage (R+) present, whereas the normally closed contacts (Normal Contacts) are active in a non-coded, or steady, output state. During this time, micro-controller integrated circuit U2 receives steady 5 VDC Phase currents coupled from solid-state relay K1, where the operating controls of solid-state relay K1 are coupled to the R+ output currents of a Phase Selective Unit (PSU).

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the TR relay is at Rest and Phase Voltage (R+) is interrupted, whereas Normally Closed contacts (Normal Contacts) remain active having steady output currents, or non-coded output currents, and flash blue LED D5 at approximately 30 ppm. During this time, micro-controller integrated circuit U2 does not receive steady 5 VDC Phase current input from solid-state relay K1.

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the Electronic TR relay is at Rest, and Phase Voltage (R+) becomes interrupted and track code currents (R−) resume, whereas micro-controller integrated circuit U2 activates only the normally closed contacts (Normal Contacts) in a steady, or non-coded output state. A loss of Phase Voltage has no effect on these contacts at this time. With Phase Voltage input lost, the electronic TR relay remains having only its normally closed contacts (Normal Contacts) active with output DC currents in a steady, or, non-coded state, and blue LED D5 flashes at approximately 30 pulses per minute. Should coded PSU R− output currents arrive while the PSU's Phase Voltage R+ currents remain missing, the TR relay turns off its normally closed (Normal) contacts, then activates its Normally Open (Reverse) contacts in a steady, or non-coded state, and maintains blue LED D5 in a flashing (30 ppm) operative state.

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the electronic TR relay is receiving coded track (R−) pulses and phase (R+) voltage is present, whereas the Normally Open (Reverse) and Normally Closed (Normal) contacts will operate at the received R− code rates coupled from a PSU providing for output currents at the received R− code rate(s). At this time, micro-controller integrated circuit U2 receives coded and or steady 5 VDC input currents from both solid-state relays K1 and K2. Micro-controller integrated circuit U2, upon receiving coded DC currents from solid-state relay K2 having controls coupled to the R− output currents from a phase selective unit (PSU), commands a shut off to the operating controls of opto-coupler U3 that provides output drive currents to solid-state relays K5 and K6 which act as the Normally Closed (or Normal) TR relay contacts.

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the electronic TR is receiving track (R−) coded currents and phase voltage (R+) is interrupted, whereas the electronic track relay activates only the normally open contacts (Reverse Contacts) in a steady output state, and flashes blue LED D5 at approximately 30 pulses per minute. At this time, micro-controller integrated circuit U2 no longer receives 5 VDC Phase input currents from solid-state relay K1.

In some embodiments, an electronic track relay (TR) emulates an electro-magnetic type track relay when the phase voltage input is restored, whereas micro-controller U2 commands blue LED D5 to turn off, and the electronic TR relay immediately resumes its normal operations in either an “at rest” or “coding” operations, as follows. If PSU R− currents are present at this time (coded AC currents are present on the rails of a railroad track), the TR relay will resume normal operations. If R− currents are not present at the time R+ is restored, then the electronic TR relay will be in its “at rest” state.

In some embodiments, an electronic track relay with an automatic default feature outputs DC currents from its normally closed electronic contact set(s) in the event the normally open electronic contact set(s) have been found to be active longer than a pre-set time period, upon which the output currents from the normally open electronic contact set(s) shall be terminated.

In some embodiments, the installation of an electronic track relay into a railroad signal system by railroad signal personnel requires only minimal labor, being the coupling of a single wire from the signal location's DC V− currents bus to the plug-in style relay socket (wire pad 21 in FIG. 8A) for B1 model railroad signal relays. The added DC V− currents wire may remain intact allowing for direct swap outs to be made with the electronic track relay and electro-magnetic type track relay, or, electro-magnetic latching relay.

One or more embodiments disclosed herein provide(s) an electronic track relay with one or more of the following effects, i.e.,

(i) emulating an electro-magnet latching track relay at rest under normal operational conditions,

(ii) emulating an electro-magnet latching track relay when at rest and phase reference voltage input is lost,

(iii) emulating an electro-magnet latching track relay when at rest and phase reference voltage input currents are lost R− track code currents become active,

(iv) emulating an electro-magnet latching track relay operating under normal conditions with phase reference voltage currents present and receiving AC track coded currents,

(v) emulating an electro-magnet latching track relay when receiving AC track coded current and phase reference voltage input is lost,

(vi) emulating an electro-magnet latching track relay when receiving AC track coded current and phase reference voltage input was lost then restored,

(vii) including an automatic self configuration feature for operations within Automatic Block Signal type railroad territories,

(viii) including an automatic self configuration feature for operations within Interlocking type railroad territories,

(ix) including an automatic on-board restoring feature for non-conforming routing relays,

(x) performing periodic self checks made for normal internal circuitry operations,

(xi) providing visual indicators for Automatic Block Signal and Interlocking configured operational modes,

(xii) providing a visual indicator having specific flash rates or steady illumination dedicated to specific faults detected,

(xiii) providing a visual indicator having varying intensity illumination for broken rail conditions detected,

(xiv) including limited compensation capabilities for correcting duty cycle errors found with received code rates,

(xv) ensuring accurate replication of received track code rates for driving code follower relays. 

1. An electronic track relay, comprising: electronic relay circuitry for receiving an input track signal coded at a pre-determined code rate, and regenerating the input track signal at said pre-determined code rate after a predetermined time delay; a driving circuit coupled to said electronic relay circuitry for receiving the delayed track signal therefrom and conducting, at the predetermined code rate, at least a power source to at least one of various components in a railroad signaling system; and a latching circuit for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system in which the electronic track relay is installed.
 2. The electronic track relay of claim 1, wherein said electronic relay circuitry comprises a micro-controller configured for automatically determining the signaling location type of the railroad signaling system in which the electronic track relay is installed, and controlling the latching circuit to latch the driving circuit into the configuration corresponding to the determined signaling location type.
 3. The electronic track relay of claim 2, wherein said micro-controller is configured for automatically determining the signaling location type of the railroad signaling system based on a power supply scheme of the railroad signaling system.
 4. The electronic track relay of claim 2, wherein said micro-controller is configured for periodically checking whether the latching circuit is in a proper position corresponding to the determined signaling location type; and if the latching circuit is determined to be in an improper position, refreshing the latching circuit to ensure that the latching circuit is in the proper position.
 5. The electronic track relay of claim 2, wherein said micro-controller is configured for periodically checking whether the latching circuit is in a proper position by sending currents along a predetermined check loop; and if the check loop is broken which indicates that the latching circuit is in an improper position, refreshing the latching circuit to ensure that the latching circuit is in the proper position.
 6. The electronic track relay of claim 2, wherein said latching circuit comprises at least one magnetic latching relay having a plurality of coils corresponding to the plurality of configurations of the driving circuit, respectively; and said micro-controller is configured for energizing one of said coils of the magnetic latching relay to latch the driving circuit into the configuration corresponding to the signaling location type of the railroad signaling system.
 7. The electronic track relay of claim 2, wherein said electronic relay circuitry further comprises a track trigger relay for receiving the input track signal from a first output of a phase selective unit of the railroad signaling system; and a phase trigger relay for receiving an input phase signal from a second output of the phase selective unit of the railroad signaling system; wherein said micro-controller is coupled to the track trigger relay and the phase trigger relay for controlling operations of the electronic track relay based on the input track signal and the input phase signal.
 8. The electronic track relay of claim 7, further comprising at least an indicator coupled to be driven by the micro-controller; wherein said micro-controller is configured to generate various alert signals via said indicator in response to at least one of the following determinations: that the input phase signal has been lost for a predetermined period; that the input track signal is out of phase with a phase reference voltage; that the latching circuit is in an improper position not corresponding to the determined signaling location type of the railroad signaling system in which the electronic track relay is installed; or that the input track signal has been active for a predetermined period.
 9. The electronic track relay of claim 8, wherein said micro-controller is configured to generate said various alert signals via said indicator by flashing said indicator at various intensities and rates.
 10. The electronic track relay of claim 1, wherein said electronic relay circuitry is configured for compensating for an increase in the duty cycle of the input track signal.
 11. An electronic track relay for conducting at least one of steady DC currents and coded DC currents to various components in a railroad signaling system, the electronic track relay comprising: a first controlling relay having an input connectable to a coding or a steady power source of the railroad signaling system to receive therefrom a square wave signal coded at a predetermined code rate and duty cycle or a steady state current, respectively; a second controlling relay for receiving a phase voltage status signal from the railroad signaling system; a micro-controller integrated circuit coupled to an output of each of the first and second controlling relays for receiving the square wave signal and the phase voltage status signal, respectively, the micro-controller integrated circuit comprising a micro-controller programmed time delay regulator circuit for delaying the received square wave signal with a predetermined time delay; an opto-coupler integrated circuit coupled to the time delay regulator circuit of the micro-controller circuit and conducting, at the pre-determined code rate or in a steady state, at least a power source to certain components in the railroad signaling system; and a dedicated DC power source coupled to at least the micro-controller integrated circuit for providing an isolated DC power source to the micro-controller integrated circuit.
 12. The electronic track relay of claim 11, being configured as a Form C, break before make, Single Pole Double Throw (SPDT) type relay and further comprising first and second solid-state relays coupled to the opto-coupler integrated circuit and together defining Normally Closed (N.C.) contacts of said SPDT type relay for conducting the at least one power source to the respective components in the railroad signaling system during an off-time period of the square wave signal.
 13. The electronic track relay of claim 12, further comprising third and fourth solid-state relays coupled to the opto-coupler integrated circuit and together defining Normally Open (N.O.) contacts of said SPDT type relay for conducting the at least one power source to the respective components in the railroad signaling system during an on-time period of the square wave signal.
 14. The electronic track relay of claim 13, wherein said micro-controller integrated circuit is configured for, in an at-rest operation, activating the N.C. contacts in a non-coded output state in response to a steady state of the phase voltage status signal.
 15. The electronic track relay of claim 13, wherein said micro-controller integrated circuit is configured for, in an at-rest operation, activating only the N.C. contacts in a non-coded output state in response to an interruption of the phase voltage status signal; said electronic track relay further comprising at least an indicator coupled to be driven by the micro-controller integrated circuit which is configured to generate an alert signal via said indicator in response to said interruption of the phase voltage status signal.
 16. The electronic track relay of claim 15, wherein said micro-controller integrated circuit is configured, in response to a presence of the square wave signal during the interruption of the phase voltage status signal, for deactivating the N.C. contacts, activating the N.O. contacts in a non-coded output state, and generating said alert signal via said indicator.
 17. The electronic track relay of claim 16, wherein said micro-controller integrated circuit is configured, in response to a restoration of the phase voltage status signal, for terminating said alert signal at said indicator, and resuming either a coding or an at-rest operation depending on whether the square wave signal is present or not, respectively.
 18. The electronic track relay of claim 13, wherein said micro-controller integrated circuit is configured, in response to a determination that the N.O. contacts have been active longer than a pre-set time period, for deactivating the N.O. contacts, and outputting DC currents from the N.C. contacts.
 19. A railroad signaling system, comprising: a phase selective unit for converting AC currents of a predetermined code rate transmitted from a section of track rails into a near square wave signal of said predetermined code rate, and outputting the near square wave signal at a first output, comparing the AC currents with a reference voltage, and outputting a phase voltage status signal based on the comparison at a second output, and an electronic magnetic latching relay comprising first and second controlling relays coupled to the first and second outputs of the phase selective unit for receiving the near square wave signal and the phase voltage status signal, respectively, a micro-controller coupled to the first and second controlling relays for receiving and outputting the near square wave signal with a predetermined time delay, and for controlling operations of the electronic magnetic latching relay based on the near square wave signal and the phase voltage status signal, a driving circuit coupled to the micro-controller for receiving the delayed near square wave signal and conducting, at the predetermined code rate, at least a power source to at least a further component of the railroad signaling system, and at least one magnetic latching relay coupled between the micro-controller and the driving circuit for latching the driving circuit into one among a plurality of configurations respectively corresponding to a plurality of different signaling location types, depending on a signaling location type of the railroad signaling system.
 20. The railroad signaling system of claim 19, further comprising: a code follower relay coupled to be driven by the driving circuit for outputting the delayed near square wave signal at the predetermined code rate on a subsequent section of the track rails. 